Vertex Pharmaceuticals is expected to report data any day now on a combination of drugs to treat cystic fibrosis, a rare, inherited disease that causes the buildup of sticky mucus in the lungs and other areas and is often fatal by age 40.

Vertex's Kalydeco, approved in 2012, was the first medicine to address the underlying genetic cause of the disease, and is hailed as a huge breakthrough for patients. But it addresses mutations affecting just a fraction of CF patients worldwide. The new drug combination, which combines Kalydeco with Lumacaftor, would expand that population dramatically.

For that reason, analysts have called the data release one of the most important events for biotech investors of the year—not just for Vertex, but for sentiment across the sector. Kalydeco alone drew $371 million in 2013 revenue. Altogether, analysts expect Vertex's cystic fibrosis medicines—if successful—could draw more than $5 billion in revenue by 2018.